Assembly Bioscie Stock Price, News & Analysis

Assembly Biosciences (Nasdaq: ASMB) presented positive Phase 1b data for its next‑generation capsid assembly modulator ABI‑4334 at AASLD The Liver Meeting® on Nov 7, 2025.

The randomized, blinded Phase 1b evaluated oral once‑daily 150 mg and 400 mg doses for 28 days in predominantly HBeAg‑negative chronic hepatitis B patients. ABI‑4334 was reported as well tolerated at both doses, produced multi‑log declines in HBV DNA and pgRNA, and achieved exposures multiple‑fold above levels anticipated to inhibit cccDNA formation. As expected for the population and short dosing interval, no reductions in HBsAg were observed. Under a collaboration, Gilead has a post‑study option to obtain an exclusive license for further development of ABI‑4334.

Assembly Biosciences (Nasdaq: ASMB) will participate in two investor conference fireside chats in October–November 2025.

Anuj Gaggar, MD, PhD, chief medical officer, will appear in a pre-recorded fireside chat available on demand beginning October 21, 2025 at 7:00 AM ET during the H.C. Wainwright Liver Disease Virtual Conference.

Jason Okazaki, CEO and president, and Dr. Gaggar will present a live fireside chat on November 12, 2025 at 11:00 AM ET at the Guggenheim 2nd Annual Healthcare Innovation Conference. Webcasts and replays will be available via the company's Events and Presentations page.

Assembly Bio (Nasdaq: ASMB) presented interim Phase 1b data for long‑acting HSV helicase‑primase inhibitor ABI‑5366 at IUSTI Europe on Oct 10, 2025. In the 350 mg weekly cohort, ABI‑5366 showed statistically significant reductions versus placebo: HSV‑2 shedding rate −94%, high viral load shedding −98%, and genital lesion rate −94%. ABI‑5366 was reported as well tolerated at evaluated doses and pharmacokinetics support weekly and potentially monthly dosing. A monthly regimen and data on ABI‑1179 are being evaluated with additional interim results expected later this fall. Assembly Bio plans to initiate Phase 2 studies of ABI‑5366 in mid‑2026.

Assembly Biosciences (Nasdaq: ASMB) has announced the pricing of two equity financings totaling $175 million. The company is conducting an underwritten public offering of 5,591,840 shares of common stock and 1,040,820 pre-funded warrants, along with accompanying Class A and Class B warrants, at $19.60 per share.

Additionally, Gilead Sciences will participate through a private placement, purchasing 2,295,920 shares with accompanying warrants. Notable investors include Commodore Capital, Blackstone Multi-Asset Investing, Farallon Capital Management, Janus Henderson Investors, and RA Capital Management. The transactions are expected to close on August 11, 2025.

Assembly Biosciences (NASDAQ:ASMB) reported positive interim results from its Phase 1b study of ABI-5366, a long-acting helicase-primase inhibitor for recurrent genital herpes. The 350mg weekly oral dose demonstrated remarkable efficacy with a 94% reduction in HSV-2 shedding rate and genital lesion rate compared to placebo over a 29-day period.

Key highlights include a 98% reduction in high viral load shedding rate and favorable safety profile. The pharmacokinetic profile supports potential for both weekly and monthly dosing regimens. Assembly Bio plans to advance directly to Phase 2 clinical studies, expected to initiate in mid-2026.

Under their collaboration agreement, Gilead Sciences maintains the right to opt in for exclusive licensing following completion of Phase 1b studies.

Assembly Biosciences (NASDAQ: ASMB) reported Q2 2025 financial results and clinical progress across its viral disease pipeline. The company ended Q2 with $75.0 million in cash, projecting operations funding into mid-2026. Revenue from Gilead collaboration increased to $9.6 million, while net loss improved to $10.2 million ($1.33 per share).

Key clinical developments include: positive Phase 1b results for ABI-4334 in chronic HBV patients, interim data from ABI-6250's Phase 1a study showing target engagement for HDV treatment, and advancement of ABI-5366 and ABI-1179 trials for genital herpes, with proof-of-concept data expected by fall 2025. The company initiated U.S. site expansion for ABI-1179's Phase 1b trial following IND clearance.

Assembly Biosciences (Nasdaq: ASMB) has reported promising interim Phase 1a data for ABI-6250, their oral hepatitis delta virus (HDV) entry inhibitor candidate. The study demonstrated a four-day half-life, supporting once-daily oral dosing, and showed dose-dependent elevations in total serum bile acids, indicating effective target engagement.

Key findings include successful completion of two single-dose cohorts (5mg and 25mg) and three multiple-dose cohorts (0.05mg, 0.2mg, and 1mg). Safety data showed mostly Grade 1 adverse events, with one Grade 2 ALT elevation in the highest dose cohort. All ALT elevations were self-limited without signs of liver injury.

The company plans to conduct additional pharmacological assessment while preparing for Phase 2 studies, positioning ABI-6250 as potentially the first oral therapy for chronic HDV infection.

Assembly Biosciences (NASDAQ:ASMB) presented Phase 1a clinical data for two novel herpes simplex virus (HSV) treatments, ABI-5366 and ABI-1179, at the STI & HIV 2025 World Congress and International Herpesvirus Workshop. The drug candidates, designed as helicase-primase inhibitors, demonstrated promising safety and pharmacokinetic profiles in healthy participants.

Key highlights include the potential for once-weekly dosing for both treatments, and once-monthly dosing for ABI-5366, representing a significant improvement over current daily dosing requirements. Both candidates showed no clinically significant food effects and are now advancing to Phase 1b trials, with interim proof-of-concept data expected in fall 2025.

Assembly Biosciences (Nasdaq: ASMB) has initiated the Phase 1b portion of its Phase 1a/b clinical trial for ABI-1179, a long-acting herpes simplex virus (HSV) helicase-primase inhibitor. The study will evaluate weekly oral doses over 29 days in participants with recurrent genital herpes, focusing on safety and antiviral activity.

The company reported that ABI-1179 demonstrated promising Phase 1a results, showing a pharmacokinetic profile supporting once-weekly oral dosing and low nanomolar potency against both HSV-1 and HSV-2 in vitro. Assembly Bio has received IND clearance to expand the study to U.S. sites.

Notably, Assembly Bio is conducting concurrent Phase 1b studies for both ABI-1179 and ABI-5366, with interim data expected in fall 2025. Under a collaboration agreement, Gilead Sciences maintains the right to opt in for an exclusive license for further development and commercialization of both candidates following review of the Phase 1b data package.